The present invention relates to a radar station placed on the surface of the earth in a vehicle, a vessel or a stationary installation, and to a radar system comprising at least two such radar stations.
Conventional radar systems for combat-control purposes are based on monostatic radar technology with sweeping directional microwave lobes. These are vulnerable to telecommunication interference and to the action of signal-homing missiles. Moreover, they are sensitive to measures reducing the radar cross section.
Bistatic and multistatic radar systems are also previously known. Such systems necessitate synchronising the stations included.
The present invention relies on signal processing which enables the use of a completely omnidirectional antenna. This is most favourable, since such an antenna, as opposed to a directional antenna, can be made very small and, hence, is easy to transport or mount on a land vehicle or a seagoing vessel. Also a low-frequency radar system, operating at frequencies of 10-500 MHz, can be made transportable in this manner.
The signal-processing equipment of the radar stations is adapted, at each moment, to calculate probabilities of target positions and their radial target velocities in relation to each individual radar station, based on the signals transmitted and received by this station. These calculated values are associated over time, which gives cumulative probability measures of target positions and radial velocities in relation to each individual radar station.
By creating a system of at least two radar stations, it is possible to calculate the position of a target by associating target positions, such as they are perceived by the different radar stations, with each other by an association of characteristic movements of the target. This takes place without having to synchronise the stations. If two stations are used, the target can be located in two dimensions; if at least three stations are used, it can be located in all three dimensions of space.
The objects of the invention are achieved by the features recited in the appended independent claims.